I have the same system as my neighbour:

1. Archer MR600 V2 4G router

2. Poynting Aerial

3. SMARTY SIM card

Both aerials are in my attic next to each other, both routers are in my study next to each other.

They have been working fine for over 2 years (apart from sometimes when it decides to use 4G+ and actually runs very slow - but that is a different problem

A couple of weeks ago my neigbours system started going very slow (6Mbs rather than the normal 50 Mbs).  Mine is still running fine.

It appears that theirs is only using 3G rather than 4G, mine is still using 4G.

I have tried a different SIM but it had no effect.

I have tried switching the aerials but it had no effect, mine still ran 4G, theirs still ran 3G.

I have pressed the RESET button at the back but it did not have any effect.

Any suggestions please?

Thanks Allen